American Tobacco used to promote its Carlton brand with the soft-sell slogan, "If you smoke, please try Carlton." Philip Morris has taken this approach a step further: If you smoke, please stop.

"Cigarette smoking causes lung cancer, heart disease, emphysema and other serious diseases in smokers," the cigarette manufacturer's Web site warns. "If you're a smoker and you're concerned about the health effects of smoking, you should quit."

 Although "cigarette smoking is addictive" and "it can be very difficult to quit," Philip Morris adds, "this shouldn't stop you from trying to do so." It provides links to several sites that offer advice to would-be ex-smokers.

 This is the new face of Philip Morris. The company hopes it will help fend off a potentially ruinous federal lawsuit that portrays the leading cigarette manufacturers as participants in a five-decade conspiracy to defraud the public. As the trial, scheduled to begin on Tuesday, gets under way, the tobacco companies want everyone to know that 1) they didn't really do anything wrong and 2) they've changed their ways.

 If that seems contradictory to you, you should have a look at the Justice Department's case. The government argues that the tobacco companies conspired to refrain from marketing reduced-risk cigarettes because they were loath to admit there was any risk to be reduced. At the same time, it faults them for selling lower-yield cigarettes as safer alternatives to full-strength brands.

 It's true that lower-yield cigarettes did not deliver the substantial health benefits that were originally expected. The main problem is that people do not smoke cigarettes in the same way as the machines that are used to measure "tar" and nicotine delivery.

 If you reduce nicotine along with the "tar," which is what the cigarette manufacturers generally did, smokers tend to compensate by taking more puffs, inhaling more deeply, holding the smoke longer, and subconsciously covering ventilation holes. The upshot is that they may not be significantly reducing their exposure to the toxins and carcinogens in tobacco smoke.

 A logical response to this problem is to maintain nicotine levels while reducing "tar" delivery. But this requires "nicotine manipulation," which the government portrays as a sinister plot to keep smokers hooked, part of the "pattern of racketeering activity" for which it is suing Philip Morris et al. under the Racketeer Influenced and Corrupt Organizations Act.

 Another problem with attacking the tobacco companies for conspiring to falsely reassure smokers by introducing lower-yield cigarettes is that the government was part of this conspiracy. It approved the testing method and required the inclusion of "tar" and nicotine ratings in cigarette ads. Continued...